2.4. Determination of Vitamin C
Vitamin C content in the fresh strawberry juices was determined using a direct iodimetric titration. An aliquot of 25
ml of a fresh strawberry juice were placed in a 250 ml erlenmeyer flask and then 2 ml of starch indicator was added.
Samples were titrated with 0.01 N iodine solutions which were previously standardized with sodium thiosulfate in
the matrix of potassium iodide. Prior to using, the sodium thiosulfate solution was standardized with a primary
standard solution of potassium iodate in acidic environment. A blank titration was performed prior to titration of
each sample (n = 4). Each ml of 0.01 N iodine is equivalent to 0.8806 mg ascorbic acid13. Results were calculated
as mg of L-ascorbic acid per 100 ml of orange juice. Each sample was prepared and analysed in duplicate